检索结果-南通市图书馆

Towards a unified nonlocal, peridynamics framework for the coarse-graining of molecular dynamics data with fractures

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2023年第7期44卷 1125-1150页

作者： H.Q.yOU X.XU y.yu S.SILLING M.D'ELIA J.FOSTER Department of Mathematics Lehigh UniversityBethlehemPA 18015U.S.A Department of Petroleum and Geosystems Engineering The University of Texas at AustinTX 78712-1139U.S.A. Center for Computing Research Sandia National LaboratoriesCA 94551-0969U.S.A.

Molecular dynamics(MD)has served as a powerful tool for designing materials with reduced reliance on laboratory ***,the use of MD directly to treat the deformation and failure of materials at the mesoscale is still largely beyond *** this work,we propose a learning framework to extract a peridynamics model as a mesoscale continuum surrogate from MD simulated material fracture data ***,we develop a novel coarse-graining method,to automatically handle the material fracture and its corresponding discontinuities in the MD displacement data *** by the weighted essentially non-oscillatory(WENO)scheme,the key idea lies at an adaptive procedure to automatically choose the locally smoothest stencil,then reconstruct the coarse-grained material displacement field as the piecewise smooth solutions containing ***,based on the coarse-grained MD data,a two-phase optimizationbased learning approach is proposed to infer the optimal peridynamics model with damage *** the first phase,we identify the optimal nonlocal kernel function from the data sets without material damage to capture the material stiffness ***,in the second phase,the material damage criterion is learnt as a smoothed step function from the data with *** a result,a peridynamics surrogate is *** a continuum model,our peridynamics surrogate model can be employed in further prediction tasks with different grid resolutions from training,and hence allows for substantial reductions in computational cost compared with *** illustrate the efficacy of the proposed approach with several numerical tests for the dynamic crack propagation problem in a single-layer *** tests show that the proposed data-driven model is robust and generalizable,in the sense that it is capable of modeling the initialization and growth of fractures under discretization and loading settings that are different from the ones used during training.

关键词： nonlocal model machine learning homogenization peridynamics material fracture

IN SITU OBSERVATION OF GROWTH BEHAVIOR AND MORPHOLOGy OF DELTA-FERRITE AS FUNCTION OF SOLIDIFICATION RATE IN AN AISI304 STAINLESS STEEL

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2006年第6期19卷 441-448页

作者： G.F.Liang C.Q.Wan J.C.Wu G.M.Zhu y.yu y.Fang Advanced Technology Institute Technology Center of BaosteelShanghai 201900China Department of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200030China

It was presented the in situ observation of growth behavior and morphology of delta-ferrite as a function of solidification rate in an AISI304 stainless steel. The specimens have been solidified and observed using confocal scanning laser microscopy (CSLM). The δ-phase always appears like cells on the sample surface when critical supercooling occurs, during which the L→δ transformation starts. The solid-liquid (S-L) interface is found to be finger shaped and has no faceted shape. γ phase appears among δ grains due to partitioning of Ni into the melt during solidification, when solidification rate is higher. The mergence of observed δ cells is possible for the steel sample cooled at 7.5℃/min. The formation of dendrites can be observed on the free surface of the steel sample cooled at 150℃/min. The size of solidified delta grains decreases from 120 to 20-80μm, and the volume fraction of solidified austenite increases with increase in solidification rate from 7.5 to 150℃/min. The relation between the tip radius of δ cell and its growth rate is deduced, and the results agree with the experimental values.

关键词： stainless steel confocal scanning laser microscopy δ-ferrite in situ observation solidification

A small-scale silica gel-water adsorption system for domestic air conditioning and water heating by the recovery of solar energy

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2020年第2期14卷 328-336页

作者： y.yu Q.W.PAN L.W.WANG Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

A small-scale silica gel-water adsorption system with modular adsorber,which utilizes solar energy to achieve the cogeneration of domestic air conditioning and water heating effect,is proposed and investigated in this paper.A heat recovery process between two adsorbers and a mass recovery process between two evaporators are adopted to improve the overall cooling and heating ***,the adsorption system is tested under different modes(different mass recovery,heat recovery,and cogeneration time)to determine the optimal operating ***,the cogeneration performance of domestic cooling and water heating effect is studied at different heat transfer fluid *** results show that the optimal time for cogeneration,mass recovery,and heat recovery are 600 s,40 s,and 40 s,*** the inlet temperature of hot water is around 85℃,the largest cooling power and heating power are 8.25 kW and 21.94 kW,*** the condition of cooling water temperature of 35℃,the obtained maximum COP,COP,and SCP of the system are 0.59,1.39,and 184.5 W/kg,respectively.

关键词： silica gel-water heat and mass recovery solar energy domestic cooling and heating

Light Scattering from Phonons in Semiconductor Quantum Dots

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light Scattering from Phonons in Semiconductor Quantum Dots

第十二届全国光散射学术会议

作者： Peter y.yu Physics Department University of CaliforniaBerkeley and Materials Sciences DivisionLawrence Berkeley National Laboratory

＜正＞There is wide spread interest recently in the science and technology of nanometer scale semiconductor structures,such as quantum *** quantized electronic and vibrational modes（phonons）of such nanostructures are expected to affect significantly their electronic and thermal *** particular the small size of these structures tend to enhance the role of surfaces,such as surface phonons

关键词：

Generation of non-classical photon pairs in atomic ensemble

在线全文

cnki会议

学校读者我要写书评

暂无评论

Generation of non-classical photon pairs in atomic ensemble

第十八届全国量子光学学术会议

作者：辜滟 C.y.Wang y.yu R.Z.Zhang D.Wei P.Zhang H.Gao F.L.Li 西安交大 Shaanxi Key Laboratory of Quantum Information and Quantum Optoelectronic Devices Xi'an Jiaotong University

It is vital to generate entangled photon pairs for the research of quantum information, quantum computation, quantum cryptography and quantum imaging. Compared to photon pairs generated by spontaneous parametric down conversion（SPDC） using nonlinear crystals, spontaneous four-wave mixing（SWMF） based on atomic ensembles can produce photon pairs with narrower linewidth and longer coherence time. In this context, we use continuous-wave operation mode to generate narrowband non-classical photon pairs via SFWM in a hot 87 Rb atomic vapor cell without buffer gas or polarization preserving coatings. We decrease the fluorescence noise in the Stokes path by detuning the pump beam away from the resonant transition and by using optical filter systems. An optical pumping beam is used to suppress the uncorrelated photon noise in the anti-Stokes path. Besides, we study the influence of experimental beam power as well as the temperature on the non-classical property of the photon pairs in this kind of vapor cell. We obtain the photon pairs with a 1/e correlation time of 40 ns and the violation of Cauchy–Schwartz inequality by a factor of 23±3. This provides a convenient and efficient method to generate photon pair sources based on an atomic ensemble.

关键词：

Research of Changbai mountain Panax ginseng's ginsenoside compound and relevant enzyme gene expression network interaction

在线全文

cnki会议

学校读者我要写书评

暂无评论

Research of Changbai mountain Panax ginseng's ginsenoside co...

第十一届全国植物基因组学大会

作者： W.Liu~#,C.Li~#,y.yu,S.Jiang,y.Wang,M.Zhang~* Jilin Agricultural University,Changchun,130118,P.R.China

Changbai mountain Panax ginseng as the material,I have extracted the ginsenosides in 15 different organs of 5 years old with soxhlet,and then determinated the content of ginseng in different organs by high performance...

关键词：

Flameless combustion for hydrogen containing fuel

在线全文

cnki会议

学校读者我要写书评

暂无评论

Flameless combustion for hydrogen containing fuel

第九届全国氢能学术会议

作者： G.F.Wang,Q.Z.Lin,C.B.Ma,y.yu,X.J.Xin University of Science and Technology of China,China

Current energy model is challenged because of the situation of energy shortage and global *** would play an important role in the coming clean energy *** example,integrated gasification combined cycle(IGCC) for power generation is an advance clean coal technology,while it converts coal(or biomass) into synthesis gas(mainly H+CO) by gasification process and after an optional carbon capture and sequestration(CCS) step the

关键词：

在线全文

cnki会议

学校读者我要写书评

暂无评论

某些非木浆的表面化学组成

国际造纸 2000年第6期19卷 23-29页

作者： y.yu K.Koljonen H.Paulapuro 冯文英唐其铮赫尔辛基工业大学造纸技术实验室赫尔辛基工业大学林产品化学实验室

借助于 ESCA(化学分析电子能谱 )研究了某些非木浆 (麦草、芦苇、甘蔗渣、竹子和红麻皮 )中表面木素和抽出物的覆盖情况，并与木浆做了比较。研究发现所有浆料的纤维表面都富集大量的木素和抽出物。在总木素含量相同的条件下，非木浆的... 详细信息

借助于 ESCA(化学分析电子能谱 )研究了某些非木浆 (麦草、芦苇、甘蔗渣、竹子和红麻皮 )中表面木素和抽出物的覆盖情况，并与木浆做了比较。研究发现所有浆料的纤维表面都富集大量的木素和抽出物。在总木素含量相同的条件下，非木浆的表面木素覆盖率要高于针叶木浆。本文分析了这方面可能存在的原因。

关键词：非木材纤维纸浆表面化学组成化学分析电子能谱木素抽出物覆盖率

广泛耐药革兰阴性菌感染的实验诊断、抗菌治疗及医院感染控制:中国专家共识

在线全文

学校读者我要写书评

暂无评论

中国感染与化疗杂志 2017年第1期17卷 82-92页

作者：王明贵 X.Guan L.He B.Hu J.Hu X.Huang G.Lai y.Li y.Liu y.Ni H.Qiu Z.Shao y.Shi M.Wang R.Wang D.Wu C.Xie y.Xu F.yang K.yu y.yu J.Zhang C.Zhuo 复旦大学附属华山医院抗生素研究所上海200040 Chinese XDR Consensus Working Group

广泛耐药革兰阴性杆菌(XDR-GNB),是指除1~2类抗菌药物(主要指多黏菌素和替加环素)外,几乎对所有类别抗菌药物均不敏感的革兰阴性杆菌。XDR-GNB常见于肠杆菌科细菌、鲍曼不动杆菌、铜绿假单胞菌和嗜麦芽窄食单胞菌等。近年来,中国XDR-GN... 详细信息

广泛耐药革兰阴性杆菌(XDR-GNB),是指除1~2类抗菌药物(主要指多黏菌素和替加环素)外,几乎对所有类别抗菌药物均不敏感的革兰阴性杆菌。XDR-GNB常见于肠杆菌科细菌、鲍曼不动杆菌、铜绿假单胞菌和嗜麦芽窄食单胞菌等。近年来,中国XDR-GNB的发生率呈不断上升趋势,由于缺乏有效的治疗药物,XDR-GNB感染成为公共卫生安全的一大威胁。我国有关感染的临床、微生物学及临床药理学专家们就XDR-GNB感染的实验室诊断、临床诊疗和医院感染控制等问题深入讨论,形成此共识。其中细菌药敏试验的抗菌药物品种及结果判定标准遵循美国临床和实验室标准化协会(CLSI)、欧洲抗菌药物敏感性试验委员会(EUCAST)或美国食品与药物监督管理局(FDA)的指南。研究提示长疗程使用广谱抗菌药物是引发XDR-GNB感染最重要的危险因素。根据现有的临床研究和实验室数据,共识提供治疗各种XDRGNB感染的联合用药推荐方案,其中常用的抗菌药物有替加环素、多黏菌素、碳青霉烯类、氨基糖苷类和磷霉素等。同时建议实行严格的感染控制措施,包括手卫生、接触隔离、主动筛查、环境消毒、去定植和抗菌药物应用管理等遏制XDRGNB感染的传播。

关键词：广泛耐药肠杆菌科细菌鲍曼不动杆菌铜绿假单胞菌嗜麦芽窄食单胞菌抗菌治疗